I wholeheartedly endorse wooden cased accordions, but with some caveats.
A resounding YES to the folk-styled Saltarelle Cleggan!
An even bigger YES to the folk-styled Castagnari Magica!
However, I have had a change of heart on the 'deluxe' cassotto offerings from Victoria, Brandoni, Petosa, Siwa & Figli etc. While they certainly look impressive wooden specimens, they are overly fancy, too large, too bulky, and far too 'mellow' to be at home in folk music. Where is the 'zingy' violin, the bandoneon that 'bubbles over,' or the sweet, reedy clarinet? Thing is, the ornate wooden Poeta and similar models are much better suited for a Jazz bar than a folk session.
'But,' you may say, 'Saltarelle and Castagnari are really expensive for their size and features' Yes, that is true; you could buy a nice preowned grand piano for the price of a Castagnari Magica. However, it is all relative! For instance, if you were to request a quote from the artisan maker of tiny, knee-perched Portative Organs with only a 2-octave keyboard, a bellows, no bass, and 24 dinky pipes, you might pay DOUBLE the price. Makes a Castagnari Magica seem cheap! Admittedly, with a Portative Organ on your knee you would have to forego the 'hillbilly' squeezebox player vibe. Apparently, there's a warning label on Portative Organs advising you may experience symptoms of becoming timeless and graceful. People may want to paint you in the renaissance style and you might well be immortalised in oil on canvas. Hmmm... I guess you get what you pay for.
For those who don't know what a Portative organ is:
And here's a review of the button version of the Magica. The significantly better piano accordion version is also available.
Finally, for what it's worth, I believe some colours of celluloid, brown pearloid (tortoiseshell finish), are just as appealing as a wood-finished accordion, and they are more durable than a wood finish. I must admit, I do not particularly favour black celluloid on anything other than a 'classical' accordion.